The present invention relates, in general, to semiconductor packages and, more particularly, to compliant standoffs for semiconductor packages.
Currently, standoffs are commonly provided by metal rings which are brazed onto the pins of the package. A typical package would contain four standoffs located generally near each corner of the package. The standoffs ensure a space remains between the semiconductor package and the board or carrier upon which it is mounted. The main purpose of the standoffs is to: prevent shorts; provide relief from stresses; and to compensate for some mismatch between the package and the board.
A current problem faced by semiconductor package manufacturers, particularly for ceramic packages, is the tendency of these packages to crack. These cracks result primarily from the packages coming into contact with other packages or the processing equipment (e.g. mark, test, wire bond). In order to prevent these cracks, package manufacturers have chamferred the edges. Additionally, some manufactures have fabricated plastic bumpers which are affixed to the sides of packages. These bumpers prevent package-to-package contact. However, these do not provide any standoff features.
One problem encountered with chamfering is that it increases the cost of a package. In addition, due to the size and design of the package environment, some packages do not have enough room between the pins and the edge of the package to permit chamfering. Further, it is suspected that chamfering causes micro-cracks to develop in the package. These micro-cracks then become large cracks when the package is subjected to stresses.
Accordingly, it is an object of the present invention to provide a compliant standoff for semiconductor packages which overcomes the above deficiencies.
A further object of the present invention is to provide a compliant standoff which eliminates the need for chamfering packages.
Another object of the present invention is to provide a compliant standoff which prevents cracking and chipping of the packages.
Still another object of the present invention is to provide a compliant standoff which combines a standoff with a compliant spacer to prevent package cracking.
Yet another object of the present invention is to provide a compliant standoff which can be used to form a pseudo leadframe of semiconductor packages.
The above and other objects and advantages of the present invention are provided by the compliant standoff described herein.